Question

1. The General Society Survey asked a sample of 1200 people how much time they spent watching TV each day. The mean number of hours was 3.0 with a standard deviation of 2.87. A sociologist claims that people watch a mean of 4 hours of TV per day. Do the data provide sufficient evidence to disprove the claim? Use ? = .05 to test the hypothesis.

2.

We have developed a regression equation to predict son’s height from father’s height:

Y = 19.4 + .737x

a.What is the intercept?

b.What is the slope?

c.What is the predicted son’s height when the father’s height is 70.8 inches?

Answer 1

Q 1)

Null hypothesis (Claim)

Alternative Hypothesis (Two tailed test )

Since population standard deviation is unknown, we use t idstribution here

Under H0, the test statistic is

Degrees of Freedom = n-1= 1199

Significance level

The critical value of t for 1199 df at 5% significance level is 1.96

The P-Value is < .00001

Since p value is less than significance level. REject H0,.

Hence, at 5% significance level, we have enough evidence to reject the claim that  people watch a mean of 4 hours of TV per day.

Q 2)

Y = 19.4+0.737X

a) Intercept = 19.4

b) Slope = 0.737

c) When X = 70.8 inches

Predicted Son's height is Y = 19.4+0.737*70.8 =71.58 inches